Springs in Backwards?

[Supra88]

I discovered my new-to-me 40 had a serious wandering problem. Upon further inspection I noticed the caster shims were in backwards, so I swapped them around and the wandering was marginally better. Something still isn't right as my caster is severely off (-) and now my drive line is colliding. Thank goodness I checked it before engaging 4 wheel drive. Let's cut to the chase here, are these springs in backwards? The short side is to the front (+) sign is to the back. I noticed my front axle appears pushed forward too. What do you think?

 

[broth9640]

Are those OME? I think the plus symbol is for the driver side. Beefier to stop cruiser lean. Can you post some more pics of the spring packs ? I will compare them to mine.

 

[Tigerstripe40]

I think I can see that the truck has a shackle reversal.
The short side of the spring should be to the rear, however, with the shackle reversal, the springs might have been reversed to keep the military wrap on the fixed hanger side. Also reversing the springs will gain some wheel base.

It looks like the driveshaft is binding, you can probably clearance the yoke so that it doesn't bind, but I would look into rotating the pinion up a bit if you can.

Those front brake lines look rather scary with how exposed they are. I would look at moving them so they are better protected. A branch sticking up on the trail could potentiall grab that SS soft line and rip the line off.

 

[broth9640]

Not sure if this helps

 

[Tokamak]

Just getting ready to install mine. . . .

Spring Installation Instructions


Front Leaf Spring Installation

8. Mount front springs with long side away from axle toward the front of the vehicle. Install the new bushings in the spring eyes and frame. Use a thin coat of grease on the bushings to aid in installation and eliminate squeaking.

Got this from the HFS installation instructions.

 

[Tokamak]

May as well check the rear

Rear Installation

Rear Leaf Spring Removal / Installation

17. Follow the instructions for front. Mount rear springs with long side away from axle toward the rear of the vehicle.

 

[Supra88]

The caster is so far negative, it must be caused by having 20" of spring to the front and 23" to the rear. Can I swap these around without issue? The mounting points look the same. The + sign is on both front springs facing rearward. The rear shocks have them too, except they're facing forward.

 

[FF LC FREAK]

You have a shackle reversal and your front springs have been flipped for added wheel base. Both of these things are typical mods that people do. With a shackle reversal, you want the thick part of the shim towards the rear. The thick part of the shim typically goes towards the shackle. You really should have your castor checked by a shop. They can tell you where your castor is. Then, you can buy the correct shims to fix any castor issues you have.

As a side note, you castor is influenced by rolling the axle one way or the other (frontwards or backwards). It doesn't care how much spring is on either side of the axle.

Good luck!

 

[Supra88]

Makes sense. It's interesting that reversing the shims made it feel better, but it obviously rotated the axle back. Hmmmm? So, I must be at positive caster without correction and shackle reversal?

How about the rear springs? The springs are long side forward and thick side of shims facing forward. Is this correct with the shackles in the back? The rear does sit lower than the front.

 

[My71FJ40]

^ Yep what FF LC FREAK said ^

 

[Supra88]

So what I'm hearing is to leave the springs as they are and buy caster shims big enough to get back in spec?

I'll address the brake line hanging down to, I missed that one.

 

[myquestoyota]

VERY clean Cruiser by the way!

 

[jim land]

first ,with this type of shackle reverse it is imposible to gain wheelbase, you have to put the short side in forward to keep it close to stock position

look at your front spring eye position under the bumper and compare it to a stock shackle set up and you going to understand

 

[Supra88]

Thanks Jim. Does it appear that my front hangers are low enough where I should be ok without a cut and turn?

 

[Toyoland66]

Makes sense. It's interesting that reversing the shims made it feel better, but it obviously rotated the axle back. Hmmmm? So, I must be at positive caster without correction and shackle reversal?

How about the rear springs? The springs are long side forward and thick side of shims facing forward. Is this correct with the shackles in the back? The rear does sit lower than the front.

I would recommend before you go any further, buy an angle finder, remove the shim altogether, and with the cruiser on level ground measure at the flat part of the top of the steering arm what your caster is currently. This will tell you what shim would be necessary to get the caster back in spec. You do want the caster to be positive for stability and self centering but there is no need to go greater than 10 deg. and as little as 5 should be fine.

The rear should have the fat end of the shim to the rear in order to level out the axle. The longer shackle will rotate the pinion up, and the shim with the fat end to the rear will rotate it back down. The exception to this would be if you have a double cardon driveshaft, in which case the pinion should point to the t-case output. If you have U joints at both ends of the driveshaft the pinion angle needs to match the t-case output angle or you will get vibrations.

As was already stated, I would leave the springs the way they are, with the long ends toward the center of the vehicle, this gives you a little more wheelbase and stability at speed. There is nothing wrong with it as long as it is done correctly.

 

[Supra88]

Alright - I checked the caster angle at the knuckle, get ready for this, I'm 12 positive degrees off. Keep in mind I flipped the existing 3.5 degree shim, so I'm guessing the springs are at +8.5 without shims.

Should I buy a 6 degree shim to get to +2.5 or go bigger? I'm running 33x12.5 tires. Toe in is about 1/4"

 

[broth9640]

Not that ditching the shackle reversal is what you had in mind, but you might consider it. Here is a tid bid from Marks Offroad Website:
Mark if you read this I hope you don't mind me quoting it here, but what you say makes a lot of sense. Not hoping to start a debate, but if this were my rig I would quit screwing around with all that castor shim nonsense and just return it back to stock shackle setup.
Cheers,
Brian




"a. SHACKLE REVERSAL Why don’t I sell this? Read my motto: I will only sell what I would be willing to install! As far as I know, Bob Hollingsworth is the only other one that is with me on this, but that still counts! In a nutshell, I think that front axle shackle reversal is a wash at best, an accident waiting to happen at worst!

Shackle reversal is most often considered as an option by people who have handling issues with their rigs. News flash: shackles are rarely the source of handling problems. I run front-mounted extended shackles on my cruisers, none of which have handling problems. If you address your real handling issues, you won’t need this. Consider this: if the stock setup was never roadworthy, it never would have left the dealership!

Here’s the theory, which I absolutely agree with. When you hit a bump with your stock suspension, the axle wants to recoil away from the bump, which means upwards and backwards (assuming you are moving forward at the time!) With the shackle mounted at the front of the spring, the spring (and consequently the axle) will need to move forward as the shackle flexes forward. This pushes the axle and the rig even harder into the ‘bump’ causing more shock and recoil. Having the shackle at the rear will allow the axle to travel away from the bump, lessening shock and recoil.

HOWEVER, THE CONVERSE IS ALSO TRUE. If you encounter a pothole, the axle in its stock configuration provides superior performance. As the ground falls away from the front tire, the axle will drop backwards towards the ground, with the shackle flexing back. A front mounted shackle will let the axle fall forward, into the abyss, so when it hits bottom, you guessed it, more shock and recoil. Really then, its just a crap shoot whether you plan on hitting more bumps or potholes.

Now for the bad news. A. Toyota never designed the cruiser for rear mounted shackles. The clearances on your driveshaft don’t matter with an axle that only flexes away from the transfer case. With shackle reversal, you have the real potential of fully collapsing your driveshaft into your transfer case! OOPS. Maybe that’s why the companies that market them offer bump stop extensions so your axle will hopefully hit the frame before your driveshaft takes out your T-case! So now you’ve got to limit suspension travel to compensate for this “improvement”

B.Now that the axle is flexing backwards, away from the steering center arm (or traditional Saginaw box) it causes a greater pull on the relay rod, as it moves away from its parallel plane to the main steering rod. This causes a condition known as ‘bump steer” . Basically, this means every time you hit a bump and your axle compresses away from your center arm or steering box, your tires will turn to the left. NICE? NOT!

C. At an off road event a few years back, I got to see an FJ40 that had the axle flex far enough back that the lugs of the tire grabbed the inner fender skirt where it protrudes around the steering box. Guess what happened?"

 

[DaveWest5150]

if you were talking about a stock truck that would be fine.. however we are talking about a spring lifted truck. this is simply adding too many lift kits together... the shackle reversal on this truck is a lift of about 2 inches with stock springs. then add in a spring that was intended to be installed the other way around... you get the issues we have here. the best way to fix this(if you want to leave both the spring lift and the shackle reversal) is to cut and turn the front housing, cut the spring pads off the axle and weld them back on with the diff pointed to the transfercase. and cut and turn the knuckles to the proper caster.

 

[longbow]

I agree with Marks offroad. I would personally never do a shackle reversal.

That being said, Dave West is dead on with how to remedy this current situation. I would cut and turn that axle and that would fix the handling as well as the drive shaft issues.

 

[mwalls54]

It also looks like your steering stablizer is attached to your axle instead of the frame.